<PAGE>

                                                                   EXHIBIT 4(ff)

                                                                     TRANSLATION

This Stock Purchase Agreement (the "Agreement") dated November 22, 2005 is made
and entered into by and among Maxcom Telecomunicaciones, S.A. de C.V.
("Maxcom"), Maxcom SF, S.A. de C.V. ("MSF" and collectively with Maxcom the
"Sellers"), Tiendas Comercial Mexicana, S.A. de C.V. ("TCM") and Controladora
Comercial Mexicana, S.A. de C.V. ("CCM" and collectively with TCM the "Buyers"),
in respect of shares representing the capital stock of MIJOLIFE, S.A. de C.V.
(the "Issuer"), in accordance with the following recitals and clauses:

                                    RECITALS

I. MAXCOM STATES, IN ITS CAPACITY AS SELLER, THAT:

1) Maxcom is a business stock corporation with variable capital (Sociedad
anonima de capital variable) duly organized under the laws of the United Mexican
States, originally under the corporate name of Amaritel, S.A. de C.V., as
evidenced in Public Instrument No. 86,115 dated February 28, 1996, which public
instrument was granted before Ignacio Soto Borja, Esq., Notary Public No. 129 in
and for the Federal District, and registered on the 11th day of June, 1996 with
the Public Registry of Commerce of the Federal District under Commercial Folio
No. 210585.

2) On February 9, 1999 Maxcom changed its corporate name to Maxcom
Telecomunicaciones, S.A. de C.V., as evidenced in Public Instrument No. 55,145
dated February 9, 1999, which public instrument was granted before Miguel
Alessio Robles, Esq., Notary Public No. 19 in and for the Federal District, and
registered on the 16th day of March, 1999 with the Public Registry of Commerce
of the Federal District under Commercial Folio No. 210585.

3) Mr. Jose Antonio Solbes is the legal representative of Maxcom and has been
vested with powers enough to assume obligations on behalf of Maxcom under this
Agreement, as evidenced in Public Instrument No. 111,911 dated August 7, 2001,
which public instrument was granted before Ignacio R. Morales Lechuga, Esq.,
Notary Public No. 116 in and for the Federal District, and registered with the
Public Registry of Commerce of the Federal District under Commercial Folio No.
210585.

4) Maxcom is the registered holder of 11'808,049 registered common shares, with
no par value, that represent 99.9970% of the capital stock of the Issuer (the
"Maxcom Shares"), out of the 11'808,400 outstanding and registered common
shares, with no par value, that represent 100% of the capital stock of the
Issuer.

5) Maxcom is interested in selling the Maxcom Shares to Buyers, together with
all the economic and corporate rights inherent thereto, including everything
legally or factually corresponding to such Maxcom Shares, upon the terms and
subject to the conditions set forth in this Agreement.

II. MSF STATES, IN ITS CAPACITY AS SELLER, THAT:

<PAGE>

1) MSF is a business stock corporation with variable capital (sociedad anonima
De capital variable) duly organized under the laws of the United Mexican States,
as evidenced in Public Instrument No. 58,185 dated February 28, 2005, which
public instrument was granted before Carlos Catano Muro Sandoval, Esq., Notary
Public No. 51 in and for the Federal District, and registered on the 4th day of
May, 2005 with the Public Registry of Commerce of the Federal District under
Commercial Folio No. 332691.

2) Mr. Jose Antonio Solbes is the legal representative of MSF and has been
vested with powers enough to assume obligations on behalf of MSF under this
Agreement, as evidenced in Public Instrument No. 58,185 dated February 28, 2005,
which public instrument was granted before Carlos Catano Muro Sandoval, Esq.,
Notary Public No. 51 in and for the Federal District, and registered on the 4th
day of May, 2005 with the Public Registry of Commerce of the Federal District
under Commercial Folio No. 332691.

3) MSF is the registered holder of 351 registered common shares, with no par
value, that represent 0.0030% of the capital stock of the Issuer (the "MSF
Shares" and collectively with the Maxcom Shares the "Issuer Shares"), out of the
11'808,400 outstanding and registered common shares, with no par value, that
represent 100% of the capital stock of the Issuer.

4) MSF is interested in selling the MSF Shares to Buyers, together with all the
economic and corporate rights inherent thereto, including everything legally or
factually corresponding to such MSF Shares, upon the terms and subject to the
conditions set forth in this Agreement.

III. TCM STATES, IN ITS CAPACITY AS BUYER, THAT:

1) TCM is a business stock corporation with variable capital (Sociedad anonima
de capital variable) duly organized under the laws of the United Mexican States,
originally under the corporate name of Auchan, S.A. de C.V., as evidenced in
Public Instrument No. 44,006 dated October 30, 1995, which public instrument was
granted before Enrique Almanza Pedraza, Esq., Notary Public No. 198 in and for
the Federal District, and registered with the Public Registry of Commerce of the
Federal District under Commercial Folio No. 204519. By means of a General
Extraordinary Shareholders Meeting held on the 11th day of March, 2003, TCM
changed its corporate name to Tiendas Comercial Mexicana, S.A. de C.V., and
amended its by-laws in their entirety, as evidenced in Public Instrument No.
82,648 dated March 17, 2003, which public instrument was granted before Enrique
Almanza Pedraza, Esq., Notary Public No. 198 in and for the Federal District.

2) Mr. Francisco Martinez de la Vega Quiroz is the legal representative of TCM
and has been vested with powers enough to assume obligations on behalf of TCM
under this Agreement, as evidenced in the public instrument referred to in the
last sentence of the preceding paragraph.

                                        2
<PAGE>

3) TCM is interested in buying the Issuer Shares, upon the terms and subject to
the conditions set forth in this Agreement, and has the funds necessary to make
the corresponding payment.

IV. CCM STATES, IN ITS CAPACITY AS BUYER, THAT:

1) CCM is a business stock corporation with variable capital (sociedad anonima
de capital variable) duly organized under the laws of the United Mexican States,
originally under the corporate name of Antonio Gonzalez e Hijo, Sociedad en
Comandita, as evidenced in Public Instrument No. 21,305 dated January 28, 1944,
which public instrument was granted before Julio Senties Garcia, Esq., Notary
Public No. 59 in and for the Federal District, and registered with the Public
Registry of Property, Commerce Section, under Book III, Volume 179, Page 84,
Entry No. 59. CCM became Comercial Mexicana, S.A., as evidenced in Public
Instrument No. 7,242 dated July 1, 1957, which public instrument was granted
before Julio Senties Garcia, Esq., the then Notary Public No. 104 in and for the
Federal District, and registered under Book III, Volume 392, Page 303, Entry No.
119. CCM became a business stock corporation with variable capital (sociedad
anonima de capital variable), as evidenced in Public Instrument No. 60,659 dated
March 5, 1982, which public instrument was granted before Mario D. Reynoso
Obregon, Esq., Notary Public No. 58 in and for the Federal District, and
registered under Commercial Folio No. 15,103. CCM changed its corporate name to
Controladora Comercial Mexicana, S.A. de C.V., as evidenced in Public Instrument
No. 60,562 dated December 9, 1988, which public instrument was granted before
Julio Senties Garcia, Esq., Notary Public No. 104 in and for the Federal
District, and registered under Commercial Folio No. 15,103.

2) Mr. Francisco Martinez de la Vega Quiroz is the legal representative of CCM
and has been vested with powers enough to assume obligations on behalf of CCM
under this Agreement, as evidenced in the public instrument referred to in the
last sentence of the preceding paragraph.

3) CCM is interested in buying the Issuer Shares, upon the terms and subject to
the conditions set forth in this Agreement, and has the funds necessary to make
the corresponding payment.

NOW, THEREFORE, the parties recognize the capacity and authority of each other
to execute this Agreement, and therefore grant the following:

                                     CLAUSES

1. PURPOSE.

Sellers hereby sell to Buyers, and Buyers hereby buy from Sellers, all the
Issuer Shares, upon the terms and subject to the conditions set forth in this
Agreement, including everything legally or factually corresponding to such
Issuer Shares, which are subject to no current or contingent litigation, claim,
liability or obligation whatsoever, as follows:

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<PAGE>

1) Maxcom sells to CCM, and CCM buys from Maxcom, 11'808,049 registered common
shares, with no par value, that represent 99.9970% of the capital stock of the
Issuer, comprised as follows:

a. 15 registered common Series B Class I shares, with no par value, represented
by Stock Certificate No. 47.

b. 11'697,111 registered common Series A Class II shares, with no par value,
represented by Stock Certificate No. 91.

c. 110,923 registered common Series B Class II shares, with no par value,
represented by Stock Certificate No. 80.

2) MSF sells to TCM, and TCM buys from MSF, 351 registered common shares, with
no par value, that represent 0.0030% of the capital stock of the Issuer,
comprised as follows:

a. 1 registered common Series A Class I share, with no par value, represented by
Stock Certificate No. 46.

b. 350 registered common Series A Class II shares, with no par value,
represented by Stock Certificates Nos. 90 and 92.

2. PURCHASE PRICE.

The parties agree that the total price for the Issuer Shares subject matter of
this purchase amounts to Pesos $ 214'594,170.84 (the "Purchase Price").

The Purchase Price is paid by Buyers to Sellers against delivery of the stock
certificates that represent the Issuer Shares, duly endorsed, as follows:

1) CCM pays to Maxcom the amount of Pesos $ 214'587,792.84 as consideration for
the Maxcom Shares acquired in accordance with Clause 1, subparagraph 1), above.

a. Concerning the aforementioned portion of the Purchase Price, the amount of
Pesos $ 21'459,417.00 shall be paid out of the Guarantee Deposit pursuant to the
Conditional Deposit Agreement No. 15262-3 dated October 18, 2005 by and among
Maxcom, TCM and Banco Nacional de Mexico, S.A., Institucion de Banca Multiple
("Banamex"), which amount shall be delivered by Banamex to Maxcom through the
Inter-bank Electronic Payment System (SPEI) managed by Banamex and by crediting
the bank account of Maxcom referred to herein below.

The remaining amount, this is, the amount of Pesos $ 193'128,375.11 is paid by
means of a wire transfer of funds through the Inter-bank Electronic Payment
System (SPEI) managed by Banamex and by crediting the following bank account of
Maxcom:

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Beneficiary:  Maxcom Telecomunicaciones, S.A. de C.V.
Bank:         IXE Banco, S.A.
Account:      30001154961-0
CLABE:        032180000115496109
Branch:       Santa Fe
City:         Mexico City, Federal District

2) TCM shall pay to MSF the amount of Pesos $ 6,378.73 as consideration for the
MSF Shares acquired in accordance with Clause 1, subparagraph 2), above. This
amount shall be paid by means of a check issued to the order of Maxcom SF, S.A.
de C.V., bearing the legend "only for deposit to the beneficiary's bank
account".

3. CLOSING DATE.

Transfer of title to the Issuer Shares and delivery of the stock certificates
duly endorsed in full in favor of Buyers are carried out on the execution date
of this Agreement.

As of the date hereof, the Sole Administrator of Issuer delivers to Buyers the
corporate books of Issuer and any other documentation related to Issuer,
including the corresponding tax and legal documentation produced from the
incorporation of Issuer to the date hereof.

4. REPRESENTATIONS AND WARRANTIES OF SELLERS.

Sellers hereby represent and warrant to Buyers that:

1. Title to Shares.

Sellers are, and will continue to be until the Closing Date, the sole and lawful
holders of the Issuer Shares.

2. Corporate Existence and Financial Statements of Issuer.

Issuer is a business stock corporation with variable capital (sociedad anonima
de capital variable) duly organized under the laws of the United Mexican States,
as evidenced in Public Instrument No. 64,673 dated September 22, 2005, which
public instrument was granted before Luis Antonio Montes de Oca Mayagoitia,
Esq., Notary Public No. 29 in and for the Federal District.

Sellers represent that the financial statements of Issuer as at October 31,
2005, as well as the balance of the capital contributions account, the net tax
profit account and the losses to be amortized account existing as of the date
hereof are those set forth in Exhibit "A" to this Agreement, all of which truly
reflect the financial condition of Issuer; and that, from such date to the
execution date of this Agreement, no adverse effect on the financial condition
or business of Issuer has occurred other than such reflected in the
aforementioned Financial Statements. Sellers further represent that Issuer has
timely and properly paid any taxes and contributions accrued until the execution
date of this Agreement,

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since Issuer has filed its tax returns and stated its income and tax liabilities
in a complete and accurate manner, provided that Sellers are not aware of any
existing audit or visit relating its tax condition by tax authorities.

Sellers represent that, as of the execution date of this Agreement, Issuer has
no contractual or otherwise relationship, and is not subject to any claim or
litigation, provided that Sellers expressly represent that Issuer is not a party
to any collective bargaining or otherwise labor or service agreement.

There is no action, claim, proceeding or lawsuit whatsoever before any court,
arbitration panel, or governmental authority, whether Mexican or foreign, that
shall have been serviced, in process or outstanding, which may have an adverse
effect on the prospectuses, financial condition, operation or results of Issuer
or the Financial Assets. On the Closing Date, Issuer is delivered free from any
contingent liabilities derived from guarantees or securities granted in favor of
third parties.

3. Authority and Capacity.

Sellers have authority and capacity to enter into this Agreement, sell the
Issuer Shares and perform their obligations derived from this Agreement.

The execution and performance of this Agreement, and the closing of the
transaction established herein, have been duly authorized by the corporate
bodies of Sellers and require no other corporate action by Sellers in order to
authorize this Agreement and the closing of the transaction established herein.

The execution and performance of this Agreement by Sellers, the closing of the
transaction established herein, and the performance of the obligations derived
from this Agreement by Sellers will not constitute: (i) a violation, conflict or
breach or default, under the articles of incorporation or by-laws of Sellers, or
any promissory note, guarantee, mortgage, trust, indenture, license, lease,
agreement, contract or otherwise material instrument executed, or obligation
assumed, by Sellers, except for such violations, conflicts, breaches or
defaults, etc. that in the aggregate have no material adverse effect on the
prospectuses, financial condition, operation or results of Sellers; or (ii) to
the best of Buyer's knowledge, a violation of any judgment, order, decree,
ordinance, law, rule, or regulation having binding effects upon Sellers.

To the best of Sellers' knowledge, no notice, registration, authorization,
consent or approval from any public entity or authority is necessary in
connection with the closing by Buyers of the transaction established in this
Agreement, other than compliance with applicable provisions of the Business
Corporations Act.

4. Capital Stock.

The capital stock of Issuer amounts to Pesos $ 6,390,000.00 and is represented
by 11'808,400 registered common shares, with no par value, fully subscribed and
paid-up, all of which shall be maintained until the Closing Date.

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5. Treasury Shares.

As of the execution date of this Agreement, there are no treasury shares issued
by Issuer.

6. Options.

No agreement, contract, option, financial instrument or right whatsoever has
been executed with, or granted in favor of, any person in respect of the
purchase of shares, whether by operation of law or under a contractual
relationship.

None person, other than the current shareholders of Issuer, is entitled to
receive a share of the profits of Issuer or hold an equity interest in its
capital stock, subscribe shares of Issuer, or otherwise become a shareholder of
Issuer.

5. REPRESENTATIONS AND WARRANTIES OF BUYERS.

Buyers hereby represent and warrant to Sellers that:

1. Authority and Capacity.

Buyers have authority and capacity to enter into this Agreement.

The execution and performance of this Agreement, and the closing of the
transaction established herein, have been duly authorized by the corporate
bodies of Buyers and require no other corporate action by Buyers in order to
authorize this Agreement and the closing of the transaction established herein.

The execution and performance of this Agreement by Buyers, the closing of the
transaction established herein, and the performance of the obligations derived
from this Agreement by Buyers will not constitute: (i) a violation, conflict or
breach or default, under the articles of incorporation or by-laws of Buyers, or
any promissory note, guarantee, mortgage, trust, indenture, license, lease,
agreement, contract or otherwise material instrument executed, or obligation
assumed, by Buyers, except for such violations, conflicts, breaches or defaults,
etc. that in the aggregate have no material adverse effect on the prospectuses,
financial condition, operation or results of Buyers; or (ii) to the best of
Buyers' knowledge, a violation of any judgment, order, decree, ordinance, law,
rule, or regulation having binding effects upon Buyers.

To the best of Buyers' knowledge, no notice, registration, authorization,
consent or approval from any public entity or authority is necessary in
connection with the closing by Buyers of the transaction established in this
Agreement, other than compliance with applicable provisions of the Business
Corporations Act.

2. Change of Management Body.

Buyers agree to hold a general ordinary shareholders meeting within a
3-calendar-day period from the execution date of this Agreement in accordance

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<PAGE>

with Article 188 of the Business Corporation Act, in order to adopt the
necessary resolutions to: i) designate a new Sole Administrator, taking into
account the resignation to be rendered by Mr. Jose Antonio Sobes Alvarez on the
date hereof, provided that Buyers, in their capacity as shareholders of Issuer,
agree to release Mr. Jose Antonio Solbes Alvarez from any liability arising out
of the performance of his duties, ii) designate a new Statutory Auditor of
Issuer, releasing Mr. Jorge Lopez Aguado Jimeno from any liability arising out
of the performance of his duties, and iii) revoke all the powers of attorney
granted by Issuer before the date hereof.

6. INDEMNITIES.

Sellers agree to be liable vis-a-vis Buyers should any third party bring an
action claiming title to the shares sold hereunder (saneamiento para el caso de
eviccion), and pay any obligation or liability of Issuer, whether current,
contingent or otherwise nature, accrued on or before the Closing Date, even if
the effects thereof occur later, provided that Sellers expressly agree that any
debts and obligations assumed by Issuer as of the Closing Date shall be borne by
such Issuer, if the same were assumed by the attorneys-in-fact designated by
Buyers at the Shareholders Meeting held on the Closing Date.

Concerning all the obligations of Issuer derived from federal, state or local
contributions, duties, and social security quotas, Sellers shall remain obliged
in accordance with statute of limitation provisions established in applicable
tax laws. Seller shall be further remain liable for any commercial, civil or
otherwise obligations accrued before the Closing Date, in accordance with
statute of limitation provisions established in applicable laws.

If any claim is made in connection with the obligations referred to in this
clause, whether on grounds of a direct or joint and several obligation of Issuer
due to events occurred before the Closing Date, Buyers shall immediately give a
notice to Mr. Jose Antonio Solbes Alvarez, who is designated by Sellers as
common representative to respond any claim brought against them, and shall
respond the same within a 15-day period, being obliged to hold Buyers free and
harmless from and against any claim brought in that regard, at no charge. Buyers
are hereby authorized by Sellers to settle any claim brought against them and
later obtain a reimbursement from Sellers upon completing the entire legal
proceeding.

Sellers expressly represent that the spin-off from which Issuer resulted has
come into effect for all applicable legal purposes as of the execution date of
this Agreement, in accordance with Article 224 Bis, paragraph d), of the
Business Corporations Act. Issuer shall not be jointly and severally obliged in
respect of any of the obligations of the spun-off company. Sellers further
represent that Issuer is fully entitled to amortize losses in the future for
income tax purposes, in accordance with applicable laws, in the amount set forth
in Exhibit A, resulting from the right originally held by Maxcom, which
transferred the same to Issuer by virtue of the spin-off. In this regard,
Sellers expressly agree to reimburse to Buyers, out of the total consideration
of the transaction, any portion pro-rata rejected by tax authorities, should
such authorities determine in

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<PAGE>

the future any differences in connection with the losses originally declared by
Maxcom; provided that, if any such differences are determined by tax
authorities, the pro-rata share of the price shall be reimbursed only and
exclusively if a final judgment is rendered by a court of competent jurisdiction
confirming the determination made by tax authorities.

7. MISCELLANEOUS.

a) Each of the parties shall bear its corresponding taxes in accordance with
applicable laws.

b) This Agreement shall be maintained in confidence by the parties until the
execution date hereof.

Notwithstanding the above, the parties acknowledge that they are subject to
certain regulatory obligations to disclose material information, and therefore,
agree that any disclosure of such information shall be permitted upon the terms
prior agreed by the parties in good faith, provided that such disclosure is
strictly necessary.

c) The parties agree that this Agreement contains the entire agreement as to the
subject matter hereof, and therefore, supersedes any prior agreement, contract
or commitment, whether verbal or written, as to the subject matter hereof. No
amendment to this Agreement shall become effective, unless if in writing and
signed by the parties.

8. NOTICES.

Any notices and communications to be given under this Agreement shall be given
in writing via fax, by hand, or overnight courier, with acknowledgment of
receipt at the following addresses:

If to Sellers:

Maxcom Telecomunicaciones, S.A. de C.V.
Guillermo Gonzalez Camarena No. 2000 - PH
Col. Centro de Ciudad Santa Fe, Mexico, D.F.
C.P. 05120 Mexico
Attention: Vice-president for Financial Affairs
Telephone: 11631005
Fax: 51471310
E-mail: jose.solbes@maxcom.com

If to Buyers:

Modulo No. 2, Conjunto Comercial Mega Mixcoac
Av. Revolucion No. 780, Colonia San Juan
Delegacion Benito Juarez, C.P. 03730, Mexico, D.F.
Attention: Rodolfo Garcia Gomez de Parada
Telephone: 52709366

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<PAGE>

Fax: 52709379
E-mail: rgarcia09@prodigy.net.mx

9. GOVERNING LAW AND JURISDICTION.

This Agreement shall be governed by and construed in accordance with the laws of
Mexico. For everything relating to the construction and performance of the
obligations derived from this Agreement, the parties expressly submit to the
jurisdiction of the courts sitting in the Federal District, waiving any other
jurisdiction they may be entitled to by reason of their present or future
domicile.

IN WITNESS WHEREOF, the parties caused their representatives to execute this
Agreement in Mexico City, Federal District, on the date first written above.

           BUYERS                                       SELLERS

TIENDAS COMERCIAL MEXICANA,                MAXCOM TELECOMUNICACIONES,
S.A. DE C.V.                               S.A. DE C.V.
CONTROLADORA COMERCIAL MEXICANA,           MAXCOM SF, S.A. DE C.V.
S.A. de C.V.

/s/ Francisco Martinez de la Vega Quiroz    /s/ Jose Antonio Solbes Alvarez
______________________________________     ____________________________________
Francisco Martinez de la Vega Quiroz       Jose Antonio Solbes Alvarez

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<PAGE>

                                    EXHIBIT A

To the Stock Purchase Agreement entered into by and among Maxcom
Telecomunicaciones, S.A. de C.V., Maxcom SF, S.A. de C.V, Tiendas Comercial
Mexicana, S.A. de C.V., and Controladora Comercial Mexicana, S.A. de C.V. in
respect of shares representing the capital stock of MIJOLIFE, S.A. de C.V.

MIJOLIFE, S.A. DE C.V.

STATEMENT OF FINANCIAL CONDITION AS AT NOVEMBER 22, 2005

<TABLE>
<CAPTION>
                                             (Pesos)
<S>                                         <C>
Assets
Current Assets                                 937,799
TOTAL ASSETS                                   937,799

Liabilities
Short-term liabilities                         107,830
TOTAL LIABILITIES                              107,830

Stockholders' Equity
Capital stock                                6'390,000
Accumulated Losses                          -5'560,031
TOTAL STOCKHOLDERS' EQUITY                     829,969

TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY     937,799
</TABLE>

                                OTHER INFORMATION

<TABLE>
<CAPTION>
                                               (PESOS)
MIJOLIFE, S.A. DE C.V.
<S>                                         <C>
CAPITAL CONTRIBUTIONS ACCOUNT (CUCA)            7'220,738.59
NET TAX PROFIT ACCOUNT (CUFIN)                             -
LOSSES TO BE AMORTIZED ACCOUNT              3,065'631,087.00
(UPDATED AS AT JUNE, 2005)
</TABLE>

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